sound 8

I never use to put my handbrake/footbrake on with autos, then someone
told me it puts stress on the g/box in park without handbrake.So I have for the last few months been putting on the handbrake/footbrake.
Now when I leave a car for a while the handbrake won't release, I have tried
pulling it hard , and just flicking it, sometimes takes 6 attempts to release
and I am worried that it will stick permanently, and it is happening on more
than one car. Any ideas.